Pros
Sharing and receiving tips and helpful advice from any IBMer in the world is priceless. Being able to work on high level solutions with high level professionals is a very intense experience for any professional.
Cons
In Chile IBM is really affected by the economy and it's very difficult to compete against smaller companies because of their prices. That being said, projects tend to be underestimated in terms of hours and deadlines become impossible to meet. All this situation is well known by the management tier, but no actions are taken beside burning out technical human resources to try to get some results which are, of course, unsatisfactory to the client. This has become a reality for almost every project I've worked on IBM Chile.